合成路线1

The known benzofuran carbinol (I) was converted to mesylate (II) upon treatment with methanesulfonyl chloride and triethylamine and then condensed with (S)-prolinol (III) at 120 C to afford adduct (IV). Subsequent chlorination of (IV) with concomitant rearrangement by means of thionyl chloride in benzene produced the 3-chloropiperidine derivative (V). The reaction of (V) with 4-hydroxybenzaldehyde (VI) in the presence of K2CO3 in DMF at 80 C furnished a mixture of six- and five-membered ring products (VII) and (VIII), which were separated by column chromatography. Condensation of the required aldehyde (VIII) with thiazolidinedione (IX) using piperidinium benzoate in refluxing toluene provided the target benzylidene thiazolidine, which was finally converted to the corresponding maleate salt.